JP3217884B2 - Liquid crystal display device and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a useful substrate material for manufacturing a liquid crystal display and to manufacturing a display device therefrom. Further, the present invention relates to a grooved polymer substrate which allows the use of flexible substrates while maintaining the space required for device walls.
e) is integrated.

[0002]

BACKGROUND OF THE INVENTION Liquid crystal display (LCD) devices are well known and are useful in many instances where light, low power and flat panel displays are desired. Typically, these devices include a set of sheet glass substrate elements, or have a half-cell in which the limited liquid crystal material between the glass substrates overlaps each other. The substrate is hermetically sealed with an encapsulant to form a cell or device. Generally, transparent electrodes are provided on the inner surface of the substrate and electric fields are applied at various points on the substrate, thereby forming and displaying an addressable screen.

Various types of liquid crystal materials are well known and are useful in devices that are twisted nematic (TN), super twisted nematic (STN) or ferroelectric displays. Ferroelectric liquid crystals are particularly useful because of their bistable properties and fast switching times. A ferroelectric liquid crystal material and a display device including the same are disclosed in U.S. Pat. No. 4,367,924 "c.
hiral Smectic Cor or H Liqu
id CrystalElectro-Optical
Device "and U.S. Pat. No. 4,563,059.
No. "Surface Stabilized Ferr
oelectric Liquid Crystal
Devices ".

It would be desirable to have a relatively light, large display area that has overhead and the like and that is used in portable devices such as computers. Certain organic polymer substrates are much lighter and more transparent than glass, and thus their use is much preferred over glass for large area lightweight displays. However, the problem of using polymer materials as substrates for liquid crystal displays is that these substrates tend to be more flexible than glass and to maintain uniform separation between closely spaced substrates to make liquid crystal displays. Must be separated by appropriate specs. In order to create a uniform electric field at low voltage and to show a uniform contrast on the entire display surface, it is necessary to precisely control the shallow cavity containing the liquid crystal material. In order to obtain such a good result, a stable ferroelectric liquid crystal display in which the size is regulated within a range of 0.1 μm in each 2 μm space is a very serious problem.

[0005] Known means for ensuring the required uniform space are to use precise short polymer fibers or spheres, such as those shown in US Patent No. 4,501,471, or Alternatively, a space material made of a photoresist material as shown in U.S. Pat. No. 4,720,173 is bonded to the substrate. Each of these methods has disadvantages. It is not easy for the fibers and spherical space particles to be evenly placed on the support to maintain space over the entire surface, and the fibers overlap to increase the height of the spacer. Further, when the device is flexible and physically stressed, the spacers may move or migrate causing the material-filled surface of the display cell to form.

[0006] The structures to be bonded must be accurately positioned on each substrate at the same height, and dimensional requirements require tolerance for difficult operations and effective liquid crystal display. The difference in chemical composition of the substrates results in differences in thermal expansion, leading to breakage of the junction at the contact surface and migration of the spacer.

One obstacle to the technology of applying the liquid crystal display (LCD) fabrication of the present invention to wider screens is the technology of wide screen photolithography (although recently limited to less than 18 inches square) and precision. By relying on sophisticated glass polishing techniques. At present, the production rate of 4-inch diagonal displays is low, sometimes less than 20%, which is based in large part on the drawbacks caused by the use of photolithographic techniques. This low percentage makes the display system expensive. The larger the screen display, the higher the price.

[0008]

SUMMARY OF THE INVENTION The present invention overcomes the disadvantages of the prior art by using a substrate element having microstructure space means integral with the substrate. The present invention relates to an integrated element which is a microstructured substrate element combining the functions of a substrate and a spacer. The present invention also includes a liquid crystal display device using a half-cell, as well as such a substrate element or a method of manufacturing such a substrate element.

Further, the present invention includes a substrate element suitable for use as a half cell for making an electrically accessible liquid crystal display. The half cell includes a polymer sheet having a microstructure profile on at least one major surface of the substrate. The contour includes a plurality of space elements with protrusions, the protrusions preferably being parallel ridges, physically and chemically integral with the substrate body, each protrusion being provided on a surface on the substrate. Raised at a normal level to hold the second substrate.

The term "chemically integrated" refers to a space element having substantially the same chemical composition as a substrate, wherein a bonding agent having a different chemical composition and another bonding layer are provided between the space element and the substrate. Means no. The surfaces around the protrusions are independently electrically conductive regions.

For incorporation in a display device, a thin transparent conductive layer is applied to the substrate, causing voltage to pass to a designated portion of the cell gap of a uniformly spaced liquid crystal display (LCD). Other devices, usually associated with liquid crystal displays, provide half cells that work with the substrate to make useful displays.

[0012] The term microstructure as used in the present invention relates to structural elements having characteristic dimensions measured in micrometer units, for example from about 1 micrometer to about 10 micrometers. The article of the present invention differs from conventionally known articles in the presence of this integrated microstructure.

The articles of the present invention are manufactured by known molding techniques, and the features of the microstructure formed integrally with the substrate are described below. This dimensional feature can be molded with very tight tolerances and is reproducible without obvious variations. This ability to provide a very precise space for the members integral with the support and to be positioned precisely over a wide area can produce a large image display with uniform features over the entire area.

The advantages of having a microstructured spacer integrated with the substrate are as follows: (1) A microstructured substrate can be manufactured with high uniformity in an area of a meter scale, thereby providing a high degree of optical uniformity. (2) the integrated microstructure can be electrically separated from the electrically adjacent conductors, thus eliminating the need for photolithography steps and being economical; and (3) separating the spacer beads or fibers. The liquid crystal display method is therefore simpler, since the need to apply or photolithographic dots or strips is eliminated. The present invention is believed to be useful in ferroelectric liquid crystals as well as TN, STN and other liquid crystal materials that require accurate and precise space regulation for high definition, large format, direct projection and projection applications.

[0015]

SUMMARY OF THE INVENTION Addressable liquid crystal devices are already known. As shown in FIG. 1, a typical twisted nematic display device 10 already known is:
A cell or envelope (e) formed by installing a set of transparent flat substrates 12 and 14 that are spaced apart from each other while overlapping each other inside the register.
nvelope). The periphery of the substrate is bonded and encapsulated with an adhesive seal material (not shown) commonly used by screen printing techniques to provide a sealed cell.

Shortly before the final seal, the shallow spaces or cavities between the substrates are filled with liquid crystal material 28.
Transparent conductive electrodes 16 (a) to 16 (e) and 18
(A) to 18 (d) may be converted to a known segment or X
-Arranged on the inner surface of the substrate in any of a Y matrix-like (as shown) form a plurality of pixels. Although only a few electrodes are shown here, in practice many electrodes will be incorporated into the cell, and this number will usually increase as the area of the cell increases.

The alignment coatings 20, 22 are provided on the inner surface of the liquid crystal display cell to contribute to the desired alignment of the liquid crystal material at the contact surface with the display surface. This ensures that the liquid crystal rotates light through an angle that is complementary to the alignment of the polarizer incorporated into the cell. Polarizing element 24,
26 relates to optics depending on the form of display and is combined with the display surface in use. When a reflective display is desired over a transmissive display, a reflective element (not shown) is combined with the bottom substrate 12. In this case, the bottom substrate 12 must not be transparent.

As mentioned above, the components of a liquid crystal display and the technology of assembling the same are well known. For details of the assembly technology, refer to “Liquid Crystals-Applic
ations and Uses ", Volume 1, B. Ba
Hadur Editing, World Scientific
Publishing Co. , (1990), Chapter 7, "Materials and Assembli"
ng Process of LCDS ".

The liquid crystal material fills the space between the substrates 12 and 14, but for purposes of illustration the opposing electrode 1
A small column of liquid crystal material 28 is shown in the area between the overlap of 6 (d) and 18 (a). 30 (a) to 30
The arrow in (e) indicates that the molecules of the liquid crystal are aligned in a 90 ° twist on the alignment layers 20 and 22 even without an electric field. Arrows 30 (a) and 30 (e) also coincide with the direction of polarization of polarizing elements 24 and 26, respectively. The electrode leads 32 (a) to 32 (e) and 36 (a) to 36 (c) are all connected to the busbars 34 and 38, and then to the schematically illustrated electronic member 40.

The twisted nematic liquid crystal device employs cholesterol liquid crystal, which is indicated by arrows 30 (a) to 3 in FIG.
As shown at 0 (e), the device has a helical or twisted molecular orientation. When an electric field is applied to the liquid crystal material through the electrodes of the device, the molecules reorient and unwind due to the electrical anisotropy of the molecules. This action causes the molecules to rotate the polarized light in the twisted state, and thus passes light without rotation in the untwisted state.

When used in combination with a polarizing element, the ability to rotate this polarized light can be displayed by either blocking or transmitting transmitted light or reflected light by the valve action of light. Surface 42 is a pixel area, which can be turned on or off simultaneously by electrodes 16 (d) and 18 (a). When the electrodes are individually incorporated into the display, the display can display images.

[0022] Ferroelectric liquid crystals are useful in display devices. Having the polarization vectors of these molecules, they are paralleled by the application of an electric field. Therefore, depending on the application of the electric field (on state),
These liquid crystal molecules are aligned in their characteristic way. Because they are bistable, they remain oriented even after the electric field for orientation is removed (off state), thereby reducing power consumption. When a field of a different polarity is applied, the liquid crystal material re-orients to a different alignment property of the electric field. As is well known, liquid crystals exhibit different orientations for different light, so that a pixel of a display device is used to switch the information display. Although the microstructure substrate element of the present invention will be described in detail hereinafter, it is particularly effective to use a ferroelectric liquid crystal for producing a gray scale device.

The electrodes are independently provided at predetermined pixels.
Addressed to give an electric field to In some cases, the electrodes scan continuously and repeatedly rapidly to provide a moving image similar to a television screen. This requires that the pixels be quickly switched on and off to change the image at short intervals. In order to rapidly switch the pixels at the appropriate voltage, the layer of liquid crystal material must be evenly thin, so the space between the substrates becomes an important issue if a uniform image is desired.

In order to obtain a wide screen display having a uniform space and resulting image, the present invention provides one or more integrated with a spacer to provide a microstructured element integrated with a substrate. Use many substrates.

FIG. 2 shows a part of the liquid crystal display device of the present invention. The device 50 has a transparent bottom substrate 52 and a transparent top substrate 54. Conductive transparent electrodes 58 and 60
Are provided on the inner surfaces of the bottom substrate and the upper substrate, respectively.
Then, it is connected to a power supply (not shown) to form an electric field between them. Optical alignment materials 62, 64 and 66 are present at various locations. Alignment material 6
4 is due to the application of an alignment layer 62 on the bottom substrate 52 and is covered by an adhesive / encapsulant 68. Thus, alignment material 64 does not perform an alignment function and can be removed if desired.
The upper substrate 54 is bonded to the top of the space rib 56 by an adhesive / encapsulant 68, which also seals the perimeter of the cell. Before completely sealing the display around the cell with adhesive / encapsulant 68, the space rib 56 and the substrate 5
A liquid crystal material (not shown) is fed into the cavities formed in 2 and 54.

Although parallel ribs are specifically described as space elements, it will be understood that other types of protrusions can also perform the same function. Thus, individual posts or other forms of protrusions in separate geometric cross sections also act as spacers and can be provided by the molding methods described hereinafter.

Although the types of parallel ribs as space elements are specifically shown here, it can be understood that other types of projections also perform the same function. Thus, other geometric cross-posts or other forms of protrusions also function as spargers and can be provided by the molding methods described hereinafter.

The lateral spacing between the protrusions or space elements is:
Depending on the particular application of the display device, it will vary considerably. The width of the space element (projection) is from about 1 or 2 μm to, for example, 25 μm.
It changes to micrometers or more micrometers. The upper limit is determined by the inactive area that can be tolerated for a given display. Typically, it is desirable to have at least 50% of the active area displayed. This means that the projected surface area of the space element is about 1 /
No more than 2 surface areas.

For a substrate where the spacing elements are substantially equal to the surface dimensions, the lateral space between the spacing elements will be at least about 1 times the width of the spacing element in the measurement direction and the width will be 10 times or more. . In addition, generally at least about 10 pixels per cm in the horizontal or vertical direction (25 per inch), about 120 or 240 pixels per cm for high resolution displays (300 to 600 per inch) and For very high resolution displays, it is desirable to have about 400 pixels per cm (1000 per inch). With 2 μm wide space ribs and 50% active area, a density of about 2,500 pixels per cm (about 6000 lines per inch) is achieved.

The substrate 52 is a thermoplastic polymer material that can be formed by a method described later, is optically transparent, has dimensional stability acceptable for various conditions in the manufacturing process,
And it can be used for a display device. Thermoplastics useful in the present invention are polycarbonate, polyvinyl chloride, polystyrene, polymethyl methacrylate,
Polyurethane polyimide, polysulfuric acid polymer (polys
ulfuric polymers) and other transparent thermoplastic polymers.

As already mentioned, the top substrate 54 without the bottom substrate microstructure is also preferably an organic polymeric material as described above or a glass known in the art. If the upper substrate has the microstructure described in the present invention, then the substrate is preferably a polymer. Although not specifically shown, the top substrate 54 can be a microstructured substrate similar to that of the bottom substrate 52, and can be applied with space ribs that intersect and contact at right angles to the space ribs 56.

Electrode materials useful in the present invention are known conductive transparent oxides such as indium-tin-oxide (ITO) and the usual materials used in liquid crystal displays. Typically, it is a conductive material deposited on the surface of the substrate by sputtering or other known methods. The conductive material is deposited on top of the space ribs because the deposition method cannot be precise enough. If left in place, this conductive area can short out through the electrode area of the superposed substrate.

Methods that can be used to remove the electrode include etching the conductive layer, such as polishing the top of the rib after deposition, protecting the desired electrode surface with photoresist or the like. When using an etching method, a positive photoresist is applied to the entire surface area. The photoresist on the upper surface of the rib is selectively irradiated with a laser beam, and the photoresist on the electrode is not exposed. The photoresist on the ribs is stripped, and the substrate is treated with an etchant. After the conductive layer on the ribs has been removed, the photoresist on the electrode surface is stripped and an alignment paint and / or other material is applied as desired.

[0034] Alignment compositions useful in the present invention are also well known. These are various polymeric materials that use solvents by commonly used spin coating or other methods of applying a thin and uniform coating on the surface of the substrate. After application, it is dried and wiped with a cloth or other material to prepare the alignment surface such that the liquid crystal molecules are juxtaposed in contact with the surface. A preferred alignment material is a nylon polymer, which can be coated with a solvent and wiped off with a cloth, such as velvet, to form a useful alignment layer.

A wide variety of adhesives / encapsulants are known and useful. Polymerizable organic materials are commonly used for plastic substrates or glass. Thermoset epoxies are well known and have good strength, while being relatively unaffected by liquid crystal compounds. Photocurable adhesives also have the advantage of relieving the stresses commonly used and created by the thermosetting process. Acrylic adhesives are conventional UV curable adhesives useful in the present invention. In some cases, ultrasonic bonding is employed to remove the adhesive by heating, flowing and re-solidifying the substrate itself to effect bonding and sealing.

In order to impart optical uniformity to a microstructured liquid crystal display, it is necessary to leave ribs in contact with a matching substrate of the liquid crystal display cell and to maintain a desired space. One solution is to adhesively couple each spacer rib to a matching substrate. This is not a simple matter, as the adhesive is typically applied to a thickness of a few microns, while the height of the ribs is only a few microns. Conventional coating methods, such as knife coating, gravure coating, etc., make the coating too thick, and also cause the adhesive to enter the channels and prevent liquid crystal filling.

Here, a new method of applying an adhesive to the rib was discovered, and this was used as a tack-off method (tack-o).
ff). This method involves diluting the adhesive with a solvent, applying it evenly to a flat carrier, drying to a thickness of a fraction of a micron, and then removing the microstructured surface of the thin adhesive layer. The rib side is rotated to tack off the upper surface of the microstructured rib. The thin adhesive never contacts the microstructured channel portion and therefore does not migrate to the channel.

FIG. 3 shows a specific embodiment of the present invention. The display device 70 includes bottom and upper substrates 72 and 74, an integrated space lip 76, and transparent conductive materials 78, 80, and 8.
2, alignment materials 84, 86, 88 and bonding agent /
It has an adhesive 90. Spacer ribs 76 are also disclosed integrally with support peaks 92. The purpose of this peak is to provide a feature that focuses ultrasonic energy on this peak and facilitates ultrasonic bonding of the support.

When using an adhesive, when the upper substrate is pressed against the spacer, the peak acts as a spacer to keep the thickness of the adhesive to a minimum. In the absence of a peak, if the pressure pressing the upper substrate against the spacer is too low, an excessively thick adhesive layer will result, and if the pressure is too high, an excessively thin adhesive layer will result in weak bonding and possible imperfections. . In any case, uneven pressing results in undesirable uneven spaces in the top and bottom substrates. Peaks help minimize this effect.

Electrode material 82 and alignment material 88 are shown above peak 92. It is difficult to avoid these materials depositing on the space ribs 76, while depositing on the other side of the substrate. The device 70 also includes a separation groove 9 formed in the substrate adjacent to the space rib 76.
4 The purpose of the isolation grooves is to reduce the likelihood of electrical contact between adjacent electrodes on substrate 72. The grooves are shown located on both sides of the space rib, but it is also effective if located only on one side of the space rib. In addition, the two grooves minimize the chance of an electrical short. There is no significant dimensional problem other than to make the grooves sufficiently narrow and deep to prevent deposition in the grooves of the conductive electrode material deposited on the support. Typically, the grooves are about 15 micrometers deep and 5 micrometers wide.
The walls of the groove may be straight or at an angle to the surface.

In general, the molding method employed has the advantage of facilitating release of the molding machine from at least one angle of the wall. Do it flat (parallel ride)
When a space means other than the above is adopted, the groove may have a form other than the parallel groove. Therefore, if individual posts are used as space elements, the groove will be an enclosed shape at the base of the post.

FIG. 4 shows the bottom and top substrates 102 and 10
4, a display device 100 having space ribs 106 (a) to 106 (f), but in practice there is a significant number of ribs and this number increases as the dimensional area of the cell increases. Electrode materials 108 and 110, alignment materials 112, 114 and 116, and adhesive / encapsulant 118 are also shown. In this embodiment, the electrodes applied to the surface of the bottom substrate are not uniform.

The features of the microstructure contained in the substrate are utilized to provide the gray scale capability of a ferroelectric liquid crystal display by changing the space between the top and bottom substrates, and therefore for certain applications. Effectively strengthen the field against voltage. Since ferroelectric liquid crystals are either on or off, their contrast does not change continuously with field strength. However, by changing the space between the electrodes at different areas of the pixel, the area of each pixel switched at a given voltage is changed, so that the vision averages the switched and unswitched areas, and It will change to an intermediate gray level that is off and turned on.

In the embodiment shown in FIG. 4, a peak 120 extending parallel to the horizontal axis of the space rib 106 is provided on the substrate surface between the space ribs 106 (a) and 106 (b).
And a valley 122. Two peaks are shown briefly for illustration, but are generally preferably 250
When about 10 peaks exist in a pixel of μm × 250 μm, a good gray scale can be adjusted. In practice, when the voltage is applied to the pixel in a slowly increasing manner, the part of the ferroelectric liquid crystal above the peak is switched first because the electric field is strongest. If the voltage is held at the point where switching just begins, the individual pixels will appear as liquid crystals in a switched strip (eg, dark) and unswitched strip (eg, bright).

Visually, the switched and unswitched areas are averaged and some degree of gray is perceived. If the voltage increases beyond the threshold at which switching starts on the peak, the strip of switch area widens as the strength of the electric field adjacent to the peak increases, and more liquid crystal is switched. The sight averages the switched and unswitched areas and feels a new level of gray. The voltage can be increased to a desired level until all the pixel areas are switched on or off entirely. In this way,
Various degrees of gray can be achieved using strongly induced liquid crystals. It has been newly found that good gray adjustment is achieved when the peak to valley height difference is about 10% of the spacer height. If the height is low, it is not effective due to the switching characteristics of the liquid crystal, for example, the stability of the display environment such as temperature, and the accuracy of regulating the voltage.

Another feature of the gray scale is that the surface in the channel has a space rib 106 that slopes slowly from left to right, rather than waving to the left.
Appears in relation to surface 124 between (b) and 106 (c). In this embodiment, the pixels darken from left to right as the electric field strength increases. This effect is worse for vision than the multistrip pattern obtained by the peaks described above. Other arrangements, such as varying heights, are also useful depending on the degree of effect achieved and ease of manufacture.

In another aspect, the combination of surfaces 126, 128 and 130 represents a means of utilizing microstructural features to provide improved color display. In this embodiment, the electrode surfaces 126, 128 and 1 of adjacent pixel areas
30 are shown at three different heights with respect to each other and to the top electrode 110. Different optical color filter materials, 132, 134 and 136, such as red, green and blue, are included in any channel above these surfaces. Maximum color intensity is achieved when the depth (d) of the liquid crystal material in the cavity is half the wavelength (λ) of the main light passing through the filter. Therefore, the optimal value of (d) is given by the equation nd
= Λ / 2, where n is the index of refraction of the liquid crystal material in the dominant wavelength transmission state.

Although the cross-sectional view of FIG. 4 illustrates features of a single display for illustrative purposes, a single display does not use all of the features and combinations other than those shown here. Can be used.

FIG. 5 shows a microstructured liquid crystal display support 140 according to the present invention, in which the alignment layer 6 shown in FIG.
2 and 66 have been removed, but also by providing directional pattern grooves on the surfaces 144 and 146 in the channels between the space ribs 142 of the bottom substrate 140 to provide a directional surface. The effect is achieved. The groove pattern includes continuous parallel grooves or smaller, but generally still has a bumpy or raggy tool to finish the molding surface.
ool) to create a directional groove pattern. Typically, the groove is about 10 to about 30% of the height of the space rib
, For example, from about 1 μm to about 3 μm.

The surfaces 144 and 146 are
Grooves are effected in the direction indicated by the line parallel to (144) or angled thereto (146). When these oriented grooves are provided in the substrate 140, the molecules of the liquid crystal material provided in the cell, even if covered by the conductive material 148, are preferably aligned straight as shown. The upper substrate (not shown) has similarly oriented grooves, whether or not space ribs are present thereon. The use of this oriented groove does not necessitate the use of a separate alignment layer of the usual type and the use of rubbing of the alignment layer to align the liquid crystal molecules.

FIG. 6 shows another embodiment of the present invention, in which the display device 150 includes a multilayer liquid crystal material. The top and bottom substrates 152 are spaced apart and are joined to a microstructured intermediate member 156 having space ribs 158. Electrically conductive substance 16
0, alignment material 162 and adhesive / encapsulant 164
Are shown here as previously described. Liquid crystal material (not shown) is contained in a cavity formed in the cell.

The microstructured liquid crystal display device of the present invention can be manufactured by a micro iterative method (micro) using emboss molding or injection molding.
It can be manufactured by replication technology. This method is known to those skilled in the art and is disclosed in U.S. Pat. Nos. 3,689,346;
Nos. 244,683 and 4,576,850, the disclosure of which is incorporated herein by reference. Basically, this method involves making a microstructured mold master using conventional methods. The mold master is filled with a polymerizable composition that polymerizes rapidly when irradiated with radiation. Upon removal of the polymerized composition from the mold master, a polymerized article having a replicated microstructured surface of the mold master is obtained.

If the main two sides of the article are molded with a microstructure, the composition is polymerized if a closed transparent mold is used, and opening the mold results in a microstructured element. To clarify the fine replica in the present invention, a master is prepared by cutting a copper alloy using a normal diamond turning lathe. This master device is used as a nickel submaster by a plating method. Each device is approximately 4 inches by 8 inches in size and has two fine duplicate spacer patterns with slightly different spacer rib heights, and each pattern is approximately 2 inches wide. Over the entire length of the The spacer ribs have a rectangular cross section, a width of 25 micrometers and a height of 2.5
Micrometers are 2.8 micrometers high in other cases.

This rib has 300 ribs per inch (1 cm per centimeter) on about 70% of the central pixel surface.
18 ribs or 118 pixels per centimeter). The heights of the two different ribs are absorbed by the relaxation of the plastic microstructure in the process of joining the mating display substrates. The second instrument is the same as the first, except that a peak profile is added to the top of the spacer cavity to provide the ribs shown in FIG.

The sub-master device is used to produce microstructured plastic spacer substrates in a single or alternate manner. In the first method, a urethane-acrylate prepolymer resin was injected into a submaster device.
After curing, the top side of the resin was smoothed and a polyester or polycarbonate film acting as a release liner was covered over the resin. Then apply this resin for about 1 minute
The composition was cured by irradiation with ultraviolet light having a wavelength of 40 to 380 nm. The second method is to heat a polycarbonate film (General Electric No. 8050) by using a
Used at 0 psi and embossed directly at 170 ° C.

The microstructured plastic substrate was sputter coated to a thickness of 2000 Å with transparent conductive indium tin oxide (ITO). This ITO
The film was then applied by vacuum evaporation with a 500 Å thick layer of silicon dioxide. The second substrate has 100 lines per inch (39.4 per centimeter).
This was prepared using a commercially available ITO-coated glass substrate having a parallel line ITO pattern with a density of (book). The substrate having this pattern was spin-coated so as to form a nylon polymer layer having a thickness of 500 Å. This nylon was a 0.5% elvamide nylon multipolymer resin (DuPont) solution of 60:40 m-cresol and methanol filtered through a 0.2 micrometer PTFE filter. Rotation is 500 for 2 seconds
rpm, then 1200 rpm for 60 seconds. The coated substrate was baked at 60 ° C. for 30 minutes and then at 70 ° C. for several hours.

Using conventional methods, the nylon layer was lightly polished in one direction using a velvet cloth to contribute to the alignment surface. The plastic and glass substrates obtained as described above are aligned by contacting the coated surfaces, placed on a laboratory heating plate maintained at about 90 ° C. on the glass surface, and an ultraviolet-curable adhesive (Noteland) The three sides of the assemblage were joined using Optical Adhesive 68) available from the company. Since the microstructured plastic substrate has a higher coefficient of thermal expansion than the glass substrate, a high temperature is adopted, and as described later, the liquid crystal filling step requires a high temperature and the plastic must not bend during this time.

The composition is a vacuum filling method commonly used in the LCD industry, and is described in Liquid Crystals-Appli, which has already been cited in the literature.
The strongly induced liquid crystal material was filled using the method described in Cations and Uses. The assembly was then sealed using a UV curable adhesive. The resulting display is approximately 1 inch (2.54 cm) square with I on each substrate.
The electrical separation between the TO electrodes was better than 1 gigaΩ.
When filled and placed between polarizations, the fluorine-containing magneto-dielectric liquid crystal material disclosed in U.S. Pat. No. 4,886,619 (Example 174) was projected onto a wall using a commercially available overhead projector. In this case, the display had a contrast greater than 10 to 1.

Here, two different adhesive systems for applying an adhesive to a microstructured substrate using a tack-off method will be described. The first adhesive is an epoxy adhesive dissolved in methyl isobutyl ketone (MIBK) (eg, Shell Chemi).
A thermoset epoxy system using a 10% solid solution of Epon 332). This solution is applied on a polyimide film at a rotation speed of 4000 rpm. After air drying for 10 minutes at room temperature, an adhesive film thickness of about 400 nm was obtained. Next, using a rubber roll, a rib is pressed against the thin adhesive film, and the adhesive is tacked off on the upper portion of the rib. The microstructure having the adhesive-coated ribs is bonded to a liquid crystal display substrate and completely cured in a furnace at 90 ° C. for 2 hours.

The second adhesive system was a 9A solution of epoxy (Norland 61) dissolved in a type A photoresist solvent.
UV curing epoxy system using a 1% solid solution. This solution is also applied to the polyimide film at a rotational speed of 4000 rpm. After drying in an oven at 60 ° C for 10 minutes, about 6
An adhesive film having a thickness of 00 nm was obtained. This thin adhesive was then tacked off to the top of the rib as described above. The microstructure having ribs coated with the adhesive was bonded to a liquid crystal display support, and was completely cured using an ultraviolet curing lamp.

[Brief description of the drawings]

FIG. 1 is a partial perspective view of a liquid crystal display device and an electronic device incorporating the same.

FIG. 2 is a partial perspective view of the liquid crystal device of the present invention.

FIG. 3 is a cross-sectional view of a liquid crystal display device showing a configuration and features of a substrate of the present invention.

FIG. 4 is a cross-sectional view of a liquid crystal display device showing a configuration and features of a substrate of the present invention.

FIG. 5 is a partial perspective view of a liquid crystal substrate in which fine structures of the present invention are arranged in parallel.

FIG. 6 is a partial perspective view of a liquid crystal display device having two separated liquid crystal layers of an intermediate separation element and a space element according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Twisted nemac display device 12, 14 ... Substrate 16a-e, 18a-d ... Electrode 20, 22 ... Alignment coating layer 24, 26 ... Polarizing element 32a-e, 36a-c ... Electrode lead wire 34, 38 ... Bus bar 40 ... Electronic assembly 50 ... Display device 52 ... Transparent bottom substrate 54 ... Transparent upper substrate 56 ... Space rib 58,60 ... Conductive electrode 62,64,66 ... Alignment material 68 ... Adhesive 70 ... Display device 72,74 ... Substrate 76 ... Integrated space rib 78,80,82 ... Transparent conductive material 84,86,88 ... Alignment material 90 ... Adhesive 92 ... Peak 94 ... Separation groove 100 ... Display device 102,104 ... Bottom and upper substrate 106a ~ F ... space ribs 108, 110 ... electrode material 112, 114, 116 ... alignment material 118 ... adhesive 120 ... Mark 122 ... valley 140 ... liquid crystal display device 142 ... space rib 144,146 ... substrate 148 ... conductive material 150 ... display device 152 ... top and bottom substrate 156 ... intermediate member 158 ... space rib 160 ... conductive material 162 ... alignment Substance 164: adhesive

Continued on the front page (72) Inventor Michael Francis Webber Minnesota 55144-1000, United States, St. Paul, 3M Center (no address) (72) Inventor Timothy Lee Hoopman United States, Minnesota 55144-1000, St. Paul, 3M Center (No address) (56) References JP-A-1-121819 (JP, A) JP-A-64-13584 (JP, A) JP-A-61-2130 (JP, A) JP-A-58-28719 (JP) , A) JP-A-53-149798 (JP, A) JP-A-62-198825 (JP, A) JP-A-63-78924 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB (Name) G02F 1/1339 500

Claims (14)

(57) [Claims] 1. An electrically addressable liquid crystal display (50,
Containing a polymer sheet having a contour of the microstructure in at least one of the major surfaces is to produce 70, 100)
The continuously board element (52,72,102), said profile comprises a plurality of impact force, it will substantially parallel (56, 76,
106) are physically and chemically integrated with the main part of the substrate, both rising to a normal extent defined by a plane from the main part of the substrate, and thereby being spaced from the main part of the first substrate. Certain second substrates (54, 74, 10)
4) a supporting lifting, the substrate surface surrounding the ridges having an electrically conductive area that can be addressed independently (58,78,108) device (52,72,102). 2. A substrate element according to claim 1, wherein it intends the is maximum at the peak. 3. The substrate element according to claim 1, wherein at least an upper portion of the ridge has an adhesive. 4. The substrate element according to claim 3, wherein the height of the adhesive ranges up to 1 micrometer. 5. The substrate element according to claim 1, wherein the substrate area surrounding the ridge changes in height according to the plane. 6. The substrate element according to claim 5, wherein the height of the surrounding area varies at least 10% of the height of the ridge. 7. A substrate element comprising a polymeric sheet of the contour of the microstructure major surface of both to organic <br/>, the contour butt
Comprises causing the pattern-like, defining physically and chemically integral with the main part of the substrate, the projections on the major surface of Izure of it will substantially parallel (158) in a plane from the surface of said principal part Raised to a normal extent, thereby forming a support for another set of substrates (152) with space from the main part, wherein the surface elements are independently addressable electrically conductive areas. Substrate element having (160) (15
6) . 8. The substrate element according to claim 7, wherein at least an upper portion of the ridge has an adhesive. 9. A set of cell walls overlap one another in a register and provide a liquid crystal material therebetween, said cell walls being addressable at opposing surfaces (58, 78, 10).
8) A liquid crystal display (50,70,100) comprising, at least one of said cell walls comprising a polymeric sheet having a contour of the microstructure in at least one of the main surfaces (52,72,102) there, the contour comprising a plurality of impact force,
Substantially flat (56,76,106) physically and chemically integrated with the main part of the substrate, both rising to the usual extent defined by a plane from the main part of the substrate, thereby From the main part of the first substrate a support for the second substrate with space (54, 74, 104) is formed, the surface being independently addressable electrically conductive areas (58, 78, 104). LCD Display surrounding said ridges having 108). 10. The display of claim 9 wherein said cell walls adhere to each other where said ridges are in contact with said second substrate. 11. A liquid crystal having a pair of opposing electrically addressable outer cell walls, and at least one intermediate cell element provided between said outer cell walls and having a microstructured contour on both major surfaces. A display device including a display cell, wherein the contour comprises a ridge pattern (158) that is physically and chemically integrated with the main portion of the substrate, wherein a protrusion on any of the main portions is from the main portion. Standing up to a normal extent defined by a plane, thereby forming a support for a set of other substrates (152) with space from the main part, the elements being independently addressable electrical conductive a sex area (160), wherein the external cell walls and intermediate cell element is deposited, the display forms at least one independent cavity on both sides of said intermediate cell elements in the overlapping register de Vise (150) . 12. A method of manufacturing a substrate element comprising molding a substrate element having a microstructure profile on the main surface of at least the substrate, the contour comprising a plurality of impact force, it Nau substantially parallel integrated with physically and chemically main part of the substrate, Izure also major first substrate Ri by it <br/> have risen to the normal extent of which is defined by the space and the plane from the main portion of the substrate A manufacturing method comprising forming a support for a second substrate spaced from a portion. 13. The method of claim 12, wherein an adhesive is applied to at least an upper portion of the ridge. 14. The method of claim 13, wherein said adhesive is applied to a thickness of 1 micrometer.